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Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 2003-0146-2976, 2005 Jun; :1-30

During February 2003, the National Institute for Occupational Safety and Health (NIOSH) received a management request for a Health Hazard Evaluation (HHE) from the Genesis Steel Services, Inc. (GSSI). GSSI requested that NIOSH: 1. Evaluate the risk that reinforcing ironworkers have for developing back and hand disorders as a result of hand-tying reinforcement steel on concrete bridge decks and other large concrete slab jobs; and, 2. Investigate whether the use of reinforcing steel battery powered tying tools can be an effective intervention for the prevention of work-related musculoskeletal disorders (WMSDs) of the upper limbs and back. In response to the request, NIOSH investigators evaluated GSSI employees' biomechanical loading during rebar tying on a freeway-bridge construction site. NIOSH investigators measured employees' wrist and forearm movement with goniometers while crew members tied reinforcing steel using three different tying methods. The employees were videotaped and the tape was analyzed to record trunk postures. NIOSH investigators analyzed the data collected and compared the results with criteria used to describe and contrast the levels of hand-wrist and low-back biomechanical loading for GSSI employees for each rebar tying technique used. Manually tying rebar at ground level using a pliers and wire involved sustained deep trunk bending and rapid, repetitive, and forceful hand-wrist and forearm movements that would require limits on the amount of time workers can safely do the work. Using a battery powered rebar tying tool significantly reduced the use of rapid and repetitive hand-wrist and forearm movements and freed one hand to support the trunk during tying. Adding an extension handle to the battery powered rebar tying tool allowed workers to tie rebar standing erect.